A Primer on Two-Stage Meta-Analysis with Individual Participant Data Obtained from Complex Sampling Surveys

The increasing availability of individual participant data (IPD) in the social sciences offers new possibilities to synthesize research evidence across primary studies. Two-stage IPD meta-analysis represents a framework that can utilize these possibilities. While most of the methodological research on two-stage IPD meta-analysis focused on its performance compared with other approaches, dealing with the complexities of the primary data has received little attention, particularly when IPD are drawn from complex sampling surveys. Complex sampling surveys often feature clustering, stratification, disproportionate sampling, and multiple stages of sample selection to obtain nationally or internationally representative data from a target population. Furthermore, IPD from these studies are likely to provide more than one effect size. To address the complexities of the primary and meta-analytic data obtained from complex surveys, we propose a two-stage IPD meta-analytic approach and illustrate its utility. To aid meta-analysts who wish to utilize complex survey data, we present a sequence of steps and discuss the methodological decisions and options within. Given its flexibility and ability to deal with the complex nature of the primary data, the proposed two-stage approach opens up new analytical possibilities for synthesizing knowledge meta-analytically.